810 Experimental CW Decoder Circuit - k3ng/k3ng_cw_keyer GitHub Wiki

Design by K3NG, Schematic Drawing Courtesy of OK1RR

This circuit can be used FEATURE_CW_DECODER (not with OPTION_CW_DECODER_GOERTZEL_AUDIO_DETECTOR) and the output would be connect to cw_decoder_pin defined in your pins file.